#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
using namespace std;
namespace qiangsir
{
	int a = 10;
	int b = 20;
	int Add(int x, int y)
	{
		return x + y;
	}
}

double Add(double x = 0, double y = 0)
{
	return x + y;
}


using qiangsir::Add;
int main()
{
	/*printf("%d\n",qiangsir::a);
	printf("%d\n",qiangsir::b);
	int c=qiangsir::Add(qiangsir::a, qiangsir::b);*/
	int c=Add(1, 2);
	cout << Add(1, 1) << "\n" << Add(1.0, 1.0) << "\n"<<Add()<< endl;
	
	return 0;
}